(ST. PAUL, MINN.) – John McCain’s campaign threatened legal action against the National Enquirer today for running a story about McCain’s running mate, Sarah Palin, allegedly having an affair with her husband’s business partner.

“The smearing of the Palin family must end. The allegations contained on the cover of the National Enquirer insinuating that Gov. Palin had an extramarital affair are categorically false. It is a vicious lie,” said McCain senior adviser Steve Schmidt.

Despite snowballing reports and rumors, Sarah Palin‘s eldest son, Track, was not part of the gang of four teenagers who criminally vandalized
44 Alaska school buses in 2005, a key culprit told The News.

“Track wasn’t with me. Track had nothing to do with it,” participant Deryck Harris, 20, said Wednesday in an exclusive interview.

Citing an anonymous judicial source, the Anchorage radio station 1080 KUDO was the first to report last week that Track Palin was the unidentified 16-year-old delinquent who not only trashed the buses but also swiped the bottle of alcohol that fueled the teen rampage.

“I was friends with him. We hung out. But he wasn’t there,” Harris said, describing the incident as a senior prank gone awry. “It was my high school mistake. It was a really bad choice. I’ve paid my restitution.”

Harris was expelled from school, wore an ankle monitor for 90 days, had to pay $4,000 and is on probation for five years. For community service, he did construction work on the Wasilla Bible Church that the Palin family attends in Wasilla.

Track Palin, 19, graduated from Wasilla High, joined the Army last year and is set to leave for Iraq this Thursday. Gov. Palin boasted of her son’s enlistment as she became John McCain‘s surprise pick for vice president.

The McCain-Palin campaign declined to comment on the issue.

But rumors quickly swirled Track was forced to join up as penance for the alleged vandalism.

“I talked to him before he joined, and he was trying to decide between the Marines and the Army. It was totally his decision,” Harris, who now lives in Anchorage, said.

“Track Palin was not involved [with the vandalism],” confirmed Capi Coon, the mother of another Wasilla teen arrested for the destructive spree.

Authorities never identified the two other juveniles accused of deflating the tires on 44 buses, breaking mirrors and disconnecting the engine block heaters of 110 buses in sub-zero weather.